The present disclosure relates generally to product flow management in a semiconductor fabrication facility, and, more specifically, to a system and method for product culmination estimation utilizing a promulgated standard queue time factor.
During fabrication, one or more semiconductor devices are typically arranged on a substrate such as a wafer, and wafers are formed into groups, or “lots.” The fabrication of complex semiconductor devices utilizes many process steps where the total fabrication of a plurality of complex semiconductor devices may take up to several months. The time employed between processes and the time for a process may vary according to a vast number of parameters. The waiting time between processes for a product may generally be referred to as the queue time. Each process may be a batch process, where a group of semiconductor devices (e.g., one or more wafer lots) are processed at the same time, or a serial process, where devices or wafers are individually processed. Furthermore, the product may be clustered together and may be transported to each process as a group. Product may be fabricated upon a substrate that may include a single product or a plurality of different products upon the substrate. The product substrates may be grouped together into a lot, wherein the size of the lot may vary or may be a standard number of substrates or products. The time to process a lot of wafers or other substrates may generally be referred to as the process or cycle time.
Process times and queue times are very important for several reasons. For example, reliability, performance and product yield can be affected by these times. Also, it is generally desirable to understand and predict the flow of wafers through the fabrication facility (fab). The monitoring and forecasting of product movement through a fab is hereinafter referred to as “product culmination forecasting”. Accordingly, what is needed is a system and method of improved product culmination forecasting.